The most controversial aspect of Trump's speech led Democrats to boo him and shout 'that's not true'

Democrats booed President Donald Trump after he announced his immigration proposal.

It was the only time Democrats booed Trump during his State of the Union address.

Democrats booed President Donald Trump, with at least one member of Congress shouting "that's not true," when the president outlined his proposed cuts to legal immigration during Tuesday night's State of the Union address.

After detailing the first two "pillars" of his immigration proposal, which involve offering a path to citizenship for roughly 1.8 million noncitizen immigrants and building a massive wall along the southern border of the US, coupled with increased funding for border security, Trump spoke of his highly controversial cuts to legal immigration.

"The third pillar ends the visa lottery — a program that randomly hands out green cards without any regard for skill, merit, or the safety of our people," he said. "It is time to begin moving towards a merit-based immigration system — one that admits people who are skilled, who want to work, who will contribute to our society, and who will love and respect our country.

"The fourth and final pillar protects the nuclear family by ending chain migration," he continued. "Under the current broken system, a single immigrant can bring in virtually unlimited numbers of distant relatives. Under our plan, we focus on the immediate family by limiting sponsorships to spouses and minor children."

Trump said the changes were necessary for economic and security reasons, and he tied two recent terrorist attacks in New York to the visa lottery program and family reunification, which Trump and some Republicans refer to as "chain migration."

"It is time to reform these outdated immigration rules, and finally bring our immigration system into the 21st century," he said. "These four pillars represent a down-the-middle compromise, and one that will create a safe, modern, and lawful immigration system."

Democrats quickly booed the president, the only time during his address that the opposition party jeered Trump.

Trump's immigration proposal was widely derided by the left and some on the right after it was announced.